Power plant for a rotary wing aircraft

A power plant (18) comprising at least one turboshaft engine (8) for driving a main rotor (3) of a rotary wing aircraft (1), in particular a helicopter, via a main gearbox (7) and a rotor shaft (6), the engine (8) being disposed substantially in the longitudinal direction, lying on or parallel with the longitudinal axis X of the aircraft (1) and behind the main gearbox (7) relative to the longitudinal direction of axis X, such that:

• the main gearbox (7) is driven in rotation by a power transmission shaft (10) connected to the free turbine (11) of the engine (8);
• the free turbine (11) is driven in rotation by the gas generator (30) of the engine (8), which is fed with air via an air inlet body (20);
• and
• the hot gas is exhausted via a nozzle (15);
• wherein said air inlet body (20) is substantially parallel to the engine (8) so that firstly its end portion (21) opening out into the ambient atmosphere is situated in front of the hot gas exhaust nozzle (15), substantially in the transverse Y,Z plane containing the shaft (6) of the main rotor (3), and secondly its second end (22) corresponding to its connection with the engine (8) is situated substantially level with the zone of the engine (8) that is rearmost relative to the longitudinal direction X.